3D Geometry Measurement Epipolar Line Defective Pixel Filtering
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Solution Overview
Problem
The light-pattern projecting method for 3D geometry measurement is hindered by multiple reflections on glossy surfaces, leading to reduced measurement accuracy, and existing solutions like anti-multiple-reflection sprays or masks are either time-consuming or impractical in clean environments.
Innovation Solution
A 3D geometry measurement apparatus and method that projects a stripe pattern onto the object, detects defective pixels affected by multiple reflections using epipolar lines, and excludes these pixels from the measurement process to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a light-pattern projecting method is used to measure large areas quickly, then measurement speed and area coverage are improved, but measurement accuracy deteriorates due to multiple reflections on glossy surfaces
Solution Approach 1:
The patent converts the harmful multiple reflections into a detectable signal by analyzing the positional relationship between projection pixels and captured pixels using epipolar lines. The system identifies pixels affected by multiple reflections through geometric constraints and excludes them from measurement, thereby transforming the harmful reflection effect into a detectable and correctable phenomenon that maintains both speed and accuracy.
2Measurement precision
If anti-multiple-reflection spray is applied to prevent multiple reflections, then measurement accuracy is improved, but the number of man-hours for rinsing increases and the process becomes impractical in clean environments
Solution Approach 1:
The patent replaces the mechanical/chemical approach of applying and rinsing anti-multiple-reflection spray with a computational/optical approach using epipolar line analysis. The system uses geometric constraints and pixel position relationships to identify and exclude multiple reflection effects through image processing algorithms, eliminating the need for physical spray application and subsequent rinsing operations.
3Measurement precision
If a mask is used to cut projected light and prevent multiple reflections, then measurement accuracy is improved, but measurement time increases and different masks are needed for each object
Solution Approach 1:
The patent extracts and removes the harmful multiple reflection components from the measurement data through epipolar line analysis. By identifying pixels that violate the geometric constraints imposed by epipolar relationships, the system separates and excludes the corrupted pixel data from the final measurement calculation, achieving accurate results without physical masks or repeated measurements.
Solution Approach 2:
The patent creates a universal solution that works for all objects and surfaces through the epipolar line analysis method. The geometric constraint-based approach is object-agnostic and can handle any glossy surface without requiring object-specific masks or adjustments, providing a single versatile methodology that maintains accuracy across diverse measurement scenarios.
4Area of stationary object
If multiple patterns are projected onto the object to measure larger area, then area coverage and measurement speed are improved, but the complexity of analyzing correspondences increases due to multiple reflections
Solution Approach 1:
The patent applies the epipolar line analysis method uniformly across all projected patterns, converting the complexity introduced by multiple reflections into a systematic filtering process. By using geometric constraints that hold for all patterns simultaneously, the method efficiently identifies and excludes corrupted correspondences from multiple patterns without requiring separate analysis for each pattern, thereby managing complexity while maintaining large-area measurement capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances measurement accuracy by effectively mitigating the impact of multiple reflections, reducing the need for time-consuming preprocessing steps and maintaining cleanliness, while allowing for faster and more precise 3D geometry measurement.
Implementation Method 1
projecting a projection image including a stripe pattern onto the object to be measured
Data Source
AI summary
A three-dimensional (3D) geometry measurement apparatus includes a projection part, a capturing part that generates a captured image of an object to be measured to which a projection image is projected, an analyzing part that obtains correspondences between projection pixel positions that are pixel positions of the projection image and captured pixel positions that are pixel positions of the captured image, a line identification part that identifies a first epipolar line of the capturing part corresponding to the captured pixel positions or a second epipolar line of the projection part corresponding to the projection pixel positions, a defective pixel detection part that detects defective pixels based on a positional relationship between the projection pixel positions and the first epipolar line or a positional relationship between the projection pixel positions and the second epipolar line, and a geometry identification part.